Fourths to frank b



(No Model.)

' P. S. GLARKSON.

SASH CORD GUIDE.

No. 475,202. Patented May 17, 1892.

x PETERS co munmmcm, vusmumu, n. c.

U ITED STATES PATENT OFFICE FRANK S. OLARKSON, OF BALTIMORE, MARYLAND, ASSIGNOR OF THREE FOURTHS TO FRANK B. SLOAN, OF SAME PLACE.

SASH-CORD GUIDE.

SPECIFICATION forming part of Letters Patent No. 475,202, dated May 17, 1892.

Application filed March 15, 1392- To aZZ whom it may concern.-

Be it known that I, FRANK S. CLARKsoN, of Baltimore, Maryland, have invented certain new and useful Improvements in Sash-Ribbon Guides; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My .invention relates to an improvement in sash-ribbon guides; and it consists of a casing and sheave, over which latter the ribbons are lead, from which the sash and its weight are suspended.

The device about to be described is identical in principle with that disclosed in Patent No. 216,767, dated June 24, 1879. The patented device shows and discloses a sheave de signed for use with a cord, Whereas the present device is designed particularly for the flat metal ribbons now commonly employed.

In the accompanying drawings, Figure 1 is r a view in side elevation of the guide, and Fig. 2 is a view in elevation of the sheave.

A represents a casing having the rounded ends B Band sheave O,the lower end B being beveled, as shown, so as to project downward within the mortise formed in the Window-frame, thereby dispensing with a securing-screw, while the upper end B is provided with a single screw-hole for the reception of a screw, which latter locks the entire casing in place. In the sheaves ordinarily employed for metal ribbons they are either provided with a plain flat face or with a fiat bearingface and side lips or projections. It is a Wellknown fact that the metal ribbons when under strain stretch unevenly at their sides, one side elongating faster than the other. WVhen this occurs or when the sheave is slightly inclined, the tendency of the ribbon is to ride up either against the side of the casing or on Serial No. 424,976. (No model.)

the flange of the sheave adjacent to the shorter edge of the ribbon. One of the principal objects of myinvention is to overcome this tendency to lateral movement of the ribbon, and I accomplish the same by forming the periphery of the roller slightly curved or convexed, as shown. This brings the strain directly on the center of the ribbon, while the side edges thereof are comparatively free of the sheave, and hence the unequal lengthening or stretching at the sides has no tendency whatever to cause the ribbon to creep laterally.

It is evident that numerous slight changes in the form might be resorted to without departing from the spirit and scope of. my invention. Hence I would have it understood that I do not wish to confine myself to the exact construction shown, but consider myself at liberty to make such slight changes and alterations as fairly fall within the spirit and scope of my invention.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

l. A sash-ribbon guide consisting, essentially, of a casing and asheave, the periphery of the latter being curved or convex, as shown, substantially as set forth.

2. The sash-ribbon guide herein described, consisting of the sheave and casing, the latter having rounded ends, of'which the upper one is perforated and the lower one beveled, the sheave havingacurved or convex periphery, substantially as shown.

In testimony whereof I have signed this specification in the presence of two subscrio ing witnesses.

FRANK S. CLARKSON.

Witnesses:

WM. ELLIs COALE, ISAAC OoALE, J r. 

